It has been proposed by Campbell (U.S. Pat. No. 3,979,498), herein incorporated by reference, to recover palladium and cesium values from nuclear fuel reprocessing wastes by oxidation of Pd ions to Pd(IV) and treatment with chloride ions to cause precipitation of Cs.sub.2 PDCl.sub.6, which can be removed.
Campbell et al have proposed, in U.S. Pat. No. 4,025,602, incorporated herein by reference, to recover transuranium elements from nuclear reactor waste by precipitation of lanthanide and actinide oxalates and subjecting the supernatant solution to treatment with a strong acid ion exchange resin to cause loading of lanthanide and actinide values on the resin.
A process in which a nitric acid solution of nuclear wastes is decomposed by sugar has been proposed by Bray et al, Invention Report HW-75565, "Use of Sugar to Neutralize Nitric Acid Waste Liquors," General Electric Co., Hanford Atomic Products Operation, Richland, Wash., Nov. 11, 1962, incorporated herein by reference. In this process, nuclear waste solution containing 5-10 M nitric acid is denitrated with sugar to an acid concentration of about 0.5 M. The solution is then neutralized with sodium hydroxide and made alkaline for long-term storage in tanks. Under these conditions, most of the fission products are precipitated along with metals such as iron. The recovery of palladium from the much larger amounts of other solids is therefore prohibitively expensive.
It will be appreciated that despite availability of a domestic source of palladium in the form of effluent from nuclear fuel reprocessing plants, there is presently no simple efficient and economical process for selective recovery of urgently needed palladium values therefrom.